1. Field of the Invention
The present invention relates to an inkjet printer equipped with an ink discharger which is operable to discharge an waste ink from a head unit of the inkjet printer.
2. Discussion of Related Art
An inkjet printer, using an inkjet principle, is easily adapted to meet a demand for a high gradation or colorization, owing to simplicity of the principle. Thus, the inkjet printer is easily arranged to perform not only a monochrome printing operation but also a full-color printing operation, by employing an ink head unit coping with a plurality of different color inks. Such an inkjet printer could suffer clogging of nozzles of an ink head unit with a thickened or dried ink sticking to or accumulated in the nozzles. There is known an inkjet printer equipped with a waste ink discharger which is operable to discharge the ink through the nozzles at a predetermined cycle or as needed, for recovering an ink ejection performance of the head unit. The waste ink discharging operation is carried out, for example, by sucking the ink through the nozzles.
As the ink commonly used in the inkjet printer, there are a pigment ink and a dye ink. The pigment ink is dried or solidified easier than the dye ink. In the inkjet printer equipped with the conventional ink discharger, the pigment ink and the dye ink are sucked through respective receiver caps as the conventional ink discharger which are arranged to cover a nozzle opening surface of the head unit, for sucking the inks through the nozzles. That is, the pigment ink and the dye ink are discharged independently of each other.
Since the pigment ink is easily dried and solidified, the pigment ink could be easily solidified in the receiver cap and/or in a tube connected to the receiver cap, thereby making it difficult to sufficiently generate a suction pressure for sucking the waste inks. In view of such a problem, there is proposed an arrangement, as disclosed in U.S. Pat. No. 6,702,422 (or corresponding to JP-2001-253095A), in which a pigment-ink receiver cap is arranged to receive the dye ink as well as the pigment ink, so that a mixture of the inks which is hardly dried and solidified is sucked by a suction pump connected to the receiver cap, so as to be discharged toward a chamber of the suction pump. In this arrangement, the pigment-ink receiver cap is arranged to first receive the pigment ink and then receive the dye ink, thereby requiring movement of one of the receiver cap and the head unit relative to the other, after receipt of the pigment ink and before receipt of the dye ink. Thus, the arrangement requires a large length of time for receiving the inks.